Ubuntu on Thumbdrive Try or Install?

[mahesh]

Installed Ubuntu 20.04.3 LTS on a 16GB thumbdrive as per these instructions: https://ubuntu.com/tutorials/create-...ick-on-windows
System boots great and then Try Ubuntu or Install Ubuntu

Then I'm prompter with Try Ubuntu or Install Ubuntu
"Install" doesn't work as it fails on Installation Type.
Click on Change - nothing
Click on + and an error pops up: No root file system is defined. Please correct this from the partitioning menu".
New Partition Table is greyed out.
I'm thinking I can't install?

"Try" makes the mousepad unusable.

Once I get this figured out, onto the next problem of installing